Conventional navigation systems have been performed navigation by reading map information recorded on DVDs.
A navigation system capable of playing back a desired DVD during navigation is described in Japanese Published Patent Application No. 2001-153674. The navigation system described in the patent document comprises a GPS receiving section for detecting a current position, a DVD-ROM drive, and a hard disk. When the DVD-ROM drive detects a DVD ejection operation, map data for a specified area is transferred from the DVD to the hard disk according to a current position detected by the GPS receiving section. At this time, a block map around a current position of a vehicle or on the route to a destination is transferred to the hard disk. After the DVD is ejected, the navigation system performs the navigation operation including a display process, using the map data on the hard disk.